Lagothrix lagotricha, the woolly monkey, is a South American or New World monkey. South American monkeys or platyrrhines comprise one of the two infraorders (Platyrrhini and Catarrhini) of anthropoid primates. They live exclusively in South and Central America, but their fossil distribution includes the Greater Antilles (MacPhee and Horovitz, 2002). The fossil record of platyrrhines extends back to the Deseadan or late Oligocene of Bolivia where they are represented by the genus Branisella (Takai and Anaya, 1996). Their presence in the New World is generally considered to be the result of a single dispersal event (Fleagle, 1999) near the end of the Eocene from the Old World, where all known basal anthropoids are found (Beard, 2002). Because South America was not connected with North America or Africa at the time, this dispersal must have involved rafting across some portion of the Atlantic.

Once in the New World, platyrrhines diverged into a variety of forms ranging in size from the smallest living anthropoid (Cebuella) at ~110 grams to the howler monkeys (Alouatta) that reach 11 kg (Fleagle, 1999). This diverse radiation of primates includes 78 living species (Fleagle, 1999) in 16 genera, one of which is the only living nocturnal anthropoid, Aotus. Their diets and locomotor adaptations are diverse, though most are at least partly frugivorous and none are primarily terrestrial.

Although the adaptations of different genera are reflected in their craniodental anatomy, platyrrhines in general retain a cranial morphology more similar to primitive anthropoids from the Eocene and Oligocene of Egypt such as Catopithecus, Parapithecus, and Aegyptopithecus than do the living Old World anthropoids (Fleagle, 1999; Simons, 2001). The research for which these CT data were collected indicates that this primitive anthropoid cranial morphology included considerable cranial pneumatization via the paranasal sinuses.

Lagothrix lagotricha is quite large, with males and females averaging 7,280 g and 7,020 g respectively (Fleagle, 1999). Lagothrix is a member of the Atelinae, a group of large-bodied arboreal platyrrhines that includes the spider monkeys, howler monkeys, and woolly spider monkeys. Although not as folivorous as their close relative Alouatta, they include a substantial amount of new leaves in their diet when fruit is scarce (Fleagle, 1999).

About the Species

This female specimen, the skull of a juvenile (incisors and M2 erupting), was collected on 26 April 1934. It was made available to The University of Texas High-Resolution X-ray CT Facility for scanning by Dr. James Rossie of Stony Brook University, courtesy of the Smithsonian Institution Division of Mammals. Scanning was funded by an NSF dissertation improvement grant to Mr. Rossie (#0100825). Funding for image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of The University of Texas at Austin.

lateral view

dorsal view

About this Specimen

This specimen was scanned by Matthew Colbert on 9 July 2002 along the coronal axis for a total of 415 slices. Each slice is 0.2003 mm thick, with an interslice spacing of 0.2003 mm and a field of reconstruction of 90.0 mm.